Selective absorption of H2S from CO2 using sterically hindered amines at high pressure

Selective absorption of H₂S from gas mixture containing H₂S and CO₂ into aqueous solutions of 2–(tert–butylamino) ethanol (TBE) and 2–amino–2–methyl–1–propanol (AMP) at different temperature was investigated at high pressure by using a static gas absorption method. The influence of temperature and contact time on the absorption of H₂S was investigated. The rates of absorption of H₂S and the selectivity factor decreased with the increase of absorption temperature. With increasing contact time for both alkanolamine solutions, the selectivity factor increased at first and then decreased.     

SELECTIVE REMOVAL OF H2S FROM PETROLEUM REFINERY GASES. II. A NEW DESULFURIZER BEHAVIOR OF DESORPTION AND THERMAL STABILITY

Desulfurizer JPE-7, a sterically hindered amine, has higher selectivity and absorption capacities than MDEA. JPE-7 has fast and complete regenerability, which has constant and lower H₂S content in the reduplicate tail gas. Thermal stability of JPE-7 is favorable for industrial operation condition. With the concentration of JPE-7 increasing, the absorption of CO₂ rapidly increases, while that of H₂S is reluctant to increase thus the selectivity and absorptivity is reluctant to increase. The optimum concentration of JPE-7 is range from 30 wt% to 40 wt%. The dimethyl yellow-methenyl blue method is recommended to determine the concentration of JPE-7 with reasonable accuracy.     

SELECTIVE REMOVAL OF H2S FROM PETROLEUM REFINERY GASES. I. A NEW DESULFURIZER BEHAVIOR OF ABSORPTION

In order to improve the selective absorption behavior of desulfurizer, a new sterically hindered amine desulfurizer, JPE-7, was developed. The performance of the desulfurizer was evaluated in laboratory. The effects of raw gas flow rate, absorption temperature and time, meanwhile JPE-7 and MDEA compound concentration on selective absorption capacity for H₂S were investigated. Results showed that the desulfurizer JPE-7 had more excellent selectivity and absorption capacities than MDEA. The commercial availability of JPE-7 was discussed.     

高效有机硫脱除溶剂研发及性能考察

针对GB 17820-2018《天然气》对商品气中总硫含量的严格要求,通过室内实验,对多种类型的有机硫脱除溶剂配方进行评价,筛选出一种具有较高有机硫脱除性能和一定脱硫选择性的物理-化学溶剂。考察了气液体积比、吸收压力及填料高度等工艺条件对该溶剂吸收性能的影响,同时也考察了再生温度、闪蒸气量和溶液性能稳定性等关键指标,明确了碳硫比对选择性的影响。在原料气中CH 3SH和COS质量浓度均为30 mg/m^3且碳硫比大于5.0的条件下,新溶剂有机硫脱除率最高可达86.87%,CO 2脱除率为76.42%,可更好地保障商品气中总硫指标,并降低商品气量损失。     

Optimal activated carbon for separation of CO2 from (H2 + CO2) gas mixture

Seven types of activated carbon were used to investigate the effect of their structure on separation of CO₂ from (H₂ + CO₂) gas mixture by the adsorption method at ambient temperature and higher pressures. The results showed that the limiting factors for separation of CO₂ from 53.6 mol% H₂ + 46.4 mol% CO₂ mixture and from 85.1 mol% H₂ + 14.9 mol% CO₂ mixture were different at 20 C and about 2 MPa. The best separation result could be achieved when the pore diameter of the activated carbon ranged from 0.77 to 1.20 nm, and the median particle size was about 2.07 lm for 53.6 mol% H₂ ? 46.4 mol% CO₂ mixture and 1.41 lm for 85.1 mol% H₂ + 14.9 mol% CO₂ mixture. The effect of specific area and pore diameter of activated carbon on separation CO₂ from 53.6 mol% H₂ ? 46.4 mol% CO₂ mixture was more significant than that from 85.1 mol% H₂ ? 14.9 mol% CO₂ mixture. CO₂ in the gas phase can be decreased from 46.4 mol% to 2.3 mol%–4.3 mol% with a two-stage separation process.     

Kinetics of (TBAF + CO2) semi-clathrate hydrate formation in the presence and absence of SDS

In this communication, the impacts of adding SDS (sodium dodecyl sulfate), TBAF (tetra-n-butylammonium fluoride) and the mixture of SDS + TBAF on the main kinetic parameters of CO₂ hydrate formation (induction time, the quantity and rate of gas uptake, and storage capacity) were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm³ batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of 1–5 wt%, and the mixture of SDS + TBAF, would increase the storage capacity of CO₂ hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO₂ hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS + TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.     

Influence of H2S Content on CO2 Corrosion Behaviors of N80 Tubing Steel

Abstract

The corrosion behaviors of N80 steel in pure CO₂ and at different partial pressure ratios of CO₂/H₂S were tested by high-temperature and high-pressure autoclave. At 90°C, with the additional H₂S to pure CO₂, the surface corrosion condition improved greatly and the corrosion rates were lower than in pure CO₂ condition. With the increase of partial pressure ratio, the corrosion rate reached a peak value at pCO₂/pH₂S = 100 and then declined. The corrosion products of the samples in different conditions were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods. The inner film is finer and denser than the outer scale.     

Analysis of energy demand for natural gas sweetening process using a new energy balance technique

Absorption by alkanolamine solvents is widely used for acid gas removal in natural gas sweetening plant. In the present research, one of the Iranian gas treating unit, Ilam Gas Treating Company (IGTC), with 3.27 mole % H₂S and 3.76 mole % CO₂ in the inlet feed gas was simulated using HYSYS V8.8. Piperazine activated solution of MDEA (PZ-MDEA) at various process operating conditions was examined to yield energy demand of natural gas sweetening process using a new energy balance technique. In this technique, the total required energy demand was related to three sections: 1. heat of vaporization, 2. sensible heat and 3. heat of the absorption. Energy balance of the absorption and regeneration columns brings a perspective of energy distribution in the sweetening plant. The effects of CO₂ and H₂S concentration at inlet feed, PZ mass fraction in activated solution of MDEA and lean amine temperature on energy distribution of the natural gas sweetening process and reboiler duty were investigated. It was finally elucidated that energy demand in the gas sweetening process or duty of reboiler is greatly influenced by heat of vaporization rate. It was also found that the heat of absorption and sensible heat have minor impacts on the energy demand.     

The effect of H<Subscript>2</Subscript>S on the selectivity of light alkenes in the FE-Mn-catalyzed Fischer-Tropsch synthesis

Iron-manganese oxides are prepared using a co-precipitation procedure and studied for the conversion of synthesis gas to light olefins. In particular, the effect of a range of preparation variables is investigated in details. In this investigation, sulfur absorption and effect of sulfur poisoning on Fe-Mn catalysts have been studied. In the Fischer-Tropsch synthesis process, the poisoning of the catalyst is one of the important parameters causing a decrease in the catalyst activity, declaring the sulfur compounds as virulent poisons in this process. In the present investigation, poisoning of Fe-Mn catalysts were performed in a gas circulation system and H₂S was injected into a circulation loop. The prepared catalysts were exposed to a mixture of H₂S and N₂ at about 450°C in the stainless-steel micro reactor via co-precipitation method. H₂S was produced by addition of H₂SO₄ to Na₂S × H₂O and this gas was mixed with an inert carrier gas (N₂). Comparing the activity and selectivity of fresh and poisoned catalysts, indicates that the selectivity and CO conversion are affected by high-level sulfur adsorbed on the catalysts. The results show that the CO conversion and selectivity with respect to methane production and coke formation were decreased, but the selectivity of light alkenes such as propylene was increased over poisoned catalysts. Characterization of both precursors and calcined catalysts by powder X-ray diffraction, BET specific surface area and thermal analysis methods such as TGA and DSC showed that the poisoning of Fe-Mn catalysts influenced the catalyst structure.     

长庆油田某天然气净化厂实现GB 17820-2018达标工艺方案研究

针对GB 17820-2018《天然气》标准中更为严格的天然气气质要求,长庆油田某天然气净化厂存在净化气中H 2S含量不满足进入长输管道要求的现象。为解决这一问题,利用HYSYS软件对该厂MDEA脱硫工艺进行了流程模拟。分析了溶液循环量、MDEA质量分数、吸收塔塔板数、原料气温度、原料气压力以及贫液入塔温度对净化气中H 2S、CO2含量的影响,并根据不同工艺参数的影响程度对参数进行排序。在此基础上,建立以最小能耗为目标函数的多参数优化模型,利用HYSYS自带的工具箱求解模型,得到满足净化气中H 2S质量浓度<5 mg/m^3、CO2摩尔分数<2.8%的最优操作参数组合。优化结果可对指导现场采取调整措施提供参考。     

硫磺回收装置加氢还原尾气超重力脱硫工艺技术研究

还原吸收尾气处理工艺广泛应用于硫磺回收装置含硫尾气处理,是减少尾气中SO_2排放最为有效的方法之一。硫磺回收装置加氢还原尾气的显著特点为:压力低,碳硫比高,要求吸收过程硫化氢脱除率高,同时具有吸收选择性。利用超重力技术强化传质及气液接触时间短等特点,将超重力技术应用于加氢尾气脱硫工艺中,考察了转速、气液比、贫液温度、气体流量等操作参数对脱硫性能及CO_2共吸收率的影响。结果表明,超重力技术应用于硫磺回收装置加氢还原尾气脱硫工艺中优势显著。     

旋转填充床中叔丁氨基乙氧基乙醇溶液选择性脱硫性能的评价

在旋转填充床中,分别以叔丁氨基乙氧基乙醇(TBEE)溶液和N-甲基二乙醇胺(MDEA)溶液为胺液,对含CO2和H2S的N2进行选择性脱硫实验。考察了旋转填充床转速及胺液中醇胺含量、胺液流量、气体流量与液体流量的比值(气液比)、吸收温度对胺液脱硫性能的影响。实验结果表明,在相同的条件下与MDEA溶液相比,TBEE溶液的脱硫率(η)和选择性因子(S)更大,体现出空间位阻胺选择性脱硫的优势;胺液中醇胺含量和胺液流量的增大可提高η、降低S;旋转填充床转速增大有利于提高η,气液比增大有助于选择性脱硫;当N2中H2S含量为0.6%～0.8%(φ)和CO2含量为8%(φ)时,在w(TBEE)=5%、旋转填充床转速1 200 r/min、胺液流量6 L/h、气液比200、吸收温度30℃的条件下,S可达22～28。     

酸性气井井筒腐蚀控制技术研究

采用高温高压腐蚀挂片、气田水化学分析、多臂井径仪测井等方法,在含H_2S/CO_2酸性气井中,研究了缓蚀剂对井下油管的保护效果。试验结果表明,评选的缓蚀剂防腐效果良好,井下加入缓蚀剂4年后,全油管平均腐蚀速率为0.04mm/a,腐蚀速率远低于腐蚀控制指标0.1mm/a;油管腐蚀主要集中在井筒上部和底部。     

The Purification of Sour Associated Gas From Daqing Oilfield Using UDS Solvent

Kinetics of CO₂ absorption into UDS (a multicomponent solvent) and MDEA solutions are measured in a disk column. Compared with MDEA, UDS shows greater absorption rate under the same operating conditions. The calculated activation energy E _a for CO₂ absorption into UDS is 44.92 kJ·mol^?1, which is higher than that of MDEA. The atmospheric absorption experiment results indicate that UDS solution shows great superiority in removing sour compounds such as H₂S and CO₂ from oilfield associated gas as compared with MDEA.     

基于CPA状态方程的高压含硫天然气压缩因子计算方法研究

对于压力高于70 MPa的含H_2S天然气,其分子之间间距缩小,极性H_2S分子之间缔合作用增强,传统SRK、PR状态方程计算高压含硫天然气的压缩因子准确性有待进一步改进。基于压力3.72～97.58 MPa、H_2S体积分数0%～70.03%的154组压缩因子修正CPA(Cubic-Plus-Association)状态方程中H_2S与CH_4、CO_2分子间二元交互作用系数,综合评价SRK、PR、CPA状态方程对压缩因子的计算精度。结果表明,对于中低压含硫天然气(p35 MPa),采用PR方程精度最高,平均相对偏差为1.12%;对于高压及超高压含硫天然气(p35 MPa),CPA方程精度最高,平均相对偏差为-1.46%。进一步采用法国ST抗硫高压PVT仪测试了4种含硫天然气在70～131 MPa条件下的138组压缩因子实测值,验证了采用CPA状态方程对于高压含硫天然气压缩因子的计算精度。     

The Induction Time of Hydrate Formation From a Carbon Dioxide-Methane Gas Mixture

Kinetics of hydrate formation from CO₂?CH₄ gas mixture has been investigated. Eight experiments in various pressures, gas compositions, and load factors (volume of injected water/volume of reactor) were performed in a 460 CC vessel. For each gas mixture, the induction time of hydrate formation has been measured and the pressure-temperature-time diagram has been plotted. The results of the experiments show that by increasing the composition of carbon dioxide in the gas, the induction time of hydrate formation decreased and by increasing the load factor, the hydrate formation rate increased.     

高含CO2天然气脱碳工艺中MDEA活化剂优选

国内高含CO_2天然气处理装置主要采用活化MDEA脱碳工艺。以DEA、MEA、PZ为活化剂,总胺物质的量浓度控制在4 mol/L。利用HYSYS软件建立运算模型,研究这3种活化MDEA溶液对CO_2的吸收性能和解吸性能,通过分析认为,高含CO_2天然气深度脱碳处理宜采用PZ为活化剂。对PZ的活化机理进行研究,发现PZ作为活化剂的效果远胜于DEA和MEA。最后,分析不同吸收温度及CO_2分压下PZ浓度变化对活化性能的影响,发现加入少量PZ即可大幅提高PZ活化MDEA溶液与CO_2反应速率,在不同CO_2分压和吸收温度的条件下均能满足高含CO_2天然气的脱碳处理要求,适应性较强,建议活化MDEA溶液中PZ的质量分数为3%~5%。     

车载等离子体重整二甲醚制氢系统性能提高途径

应用自制的车载等离子体富氢气体制备装置和二甲醚（DME）部分氧化重整制氢实验测量系统,进行了利用排气余热提高该反应氢产率的研究。考察了反应温度、空/醚体积比(V_A/V_D)和Fe基催化剂对系统性能的影响。结果表明,随着反应温度的升高,DME部分氧化重整制氢反应的DME转化率逐渐升高,H₂产率先增大后减小,650℃时达最大值20.3%;温度保持为600℃时,随着V_A/V_D的增加,氢产率先增加后减小,在V_A/V_D =3.0时,H₂产率取得最高值22.2%;提高温度可降低对过量空气的依赖,但高温下H₂选择性小于常温下的;温度超过500℃后,以活性炭为载体的Fe基催化剂能够显著提高部分氧化的反应速率,从而提高H₂产率和DME转化率。利用发动机排气废热可以提高制氢系统的综合性能,但反应温度不宜超过650℃。     

Implementation of CPA EoS for simultaneous solubility modeling of CO2 and H2S in ionic liquid [OMIM][Tf2N]

In this study, solubility of pure CO₂ and H₂S and their mixture in [OMIM][Tf₂N] modeled applying CPA EoS. CPA combines the SRK equation with an advanced association term, which is similar to that of SAFT. From a practical point of view, the target in the CPA project was to develop a thermodynamic model capable of describing complex equilibria of mixtures containing polar/associating chemicals through a simple procedure with respect to the SAFT.

The AAD% for binary systems, including H₂S+ IL and CO₂+ IL are 6.81, 5.21 respectively. Moreover, AAD% equal to 13.89 was achieved for the ternary system.